Abstract: The aim of this study was to determine the distribution and biologically characterize Potato Virus Y (PVY) infecting potato (Solanum tuberosum L.) in Kenya. A survey was done in the main potato growing areas in Kenyan. Biological characterization of the PVY Kenyan variants was done by inoculating them into selected indicator plants mechanically and by aptarate aphids Myzus persicae and Macrosiphum euphorbiae. PVY disease incidence was highest in Imenti Central (91%) followed by Nyandarua North (76%) and Kiambu (73%). The least infection was in Bomet (2%), followed by Narok South district (10%). There was significant mean difference in the ELISA positive samples among the regions of survey (F=10.08, p=0.0001). Meru region had the highest PVY disease infection, although not statistically different from Kiambu, Nyandarua, Uasin Gishu and Mt. Elgon regions. All the indicator plants tested became infected with PVY and expressed varied symptoms except Datura stramonium and Chenopodium murale. M. persicae was a more efficient transmitter of PVY at p=0.037 than M. euphorbiae. S. nigrum, Physalis floridana, Datura metel, Nicotiana glutinosa, and Nicotiana tabacum were the most suitable in detecting PVY. Regions with low PVY incidence should be considered as sites for seed multiplication and continuous surveillance for PVY should be done so as to understand the spread pattern in Kenya.
Keywords: Incidence, Myzus persicae, Macrosiphum euphorbiae, potato, Survey.

Abstract: Two completely randomized glasshouse screening experiments in design coupled with two molecular screening assays were carried out at Kenya Agricultural Research Institute’s Muguga South and Trypanosomiasis Research Centres both located at 2095m above sea level at the (1o 13’ 53.0” S) and (36o 38’ 1.1” E) of Kiambu County in Kenya. The aim of the studies was to determine the efficacy of four different primer pairs in the detection of Ustilago kamerunensis in selected asymptomatic (non-smutting) napier grass accessions’ tissues at expected PCR band sizes and to investigate whether the selected accessions were completely resistant (immune) or tolerant to the pathogen. The glasshouse screening results revealed predominant differences in the smutting proportions of the accessions ranging from 0% to 90.22%. These differences were further manifested in the accession’s respective neighbour joining groups where a heterogeneous pattern in response to disease challenge was observed. The molecular screening assays demonstrated that internal transcribed spacer (1 / 4) primers were better in detecting the pathogen in the asymptomatic accessions’ tissues followed by β-tubulin (F1 / R2) primers at the expected band size. The molecular screening showed that ten out of eleven asymptomatic accessions and the four checks despite not smutting had the pathogen in their tissues with exception of accession 16806 which did not exhibit any in both molecular trials. The results indicated that the ten out of eleven selected asymptomatic accessions to head smut disease seemed tolerant and only 16806 seemed completely resistant (immune) to the napier head smut disease.
Keywords: Dairy Industry, Phytosanitary measures, Screening, Head smut, Primers, Africa.

Effect of Different Irrigation Regimes on Grain Yield and Quality of Some Egyptian Bread Wheat Cultivars

Abstract: Two field experiments were conducted in the successive winter seasons 2011/2012 and 2012/2013 at the Agricultural Experiment and Research Station, Faculty of Agriculture, Cairo University to study the effect of irrigation regime (I1: full irrigation 5 irrigation, I2: skipping 2nd irrigation, I3: skipping 3rd irrigation, I4: skipping 4th irrigation and I5: skipping 5th irrigation) on yield and quality of five wheat cultivars (Sids 12, Gemmeiza 9, Sakha 93, Misr 1 and Misr 3). A spilt-plot in a randomized complete block arrangement design with three replications was used. Results showed that skipping irrigation at various growth stages had significant effect on days to heading, days to maturity and days from heading to maturity. Skipping the second or the third irrigation led to early heading and early maturity. Also, results showed that skipping irrigation at various growth stages significantly decreased plant height, number of tillers m-2, number of spikes m-2, spike length, 1000-kernel weight, grain, straw and biological yields and harvest index in both seasons. However, protein content was decreased by skipping irrigation at various growth stages compared with normal irrigation in two seasons. Among wheat cultivars, Sids 12 cultivar ranked 1st in all yield traits and protein content in both season. It concluded that Sids 12 cultivar was more tolerant for drought stress compared with other wheat cultivars in both seasons.
Keywords: Wheat, Cultivars, Irrigation regime, Skipping, Heading, Maturity, Yield, Grain quality, straw, biological, Protein.

Abstract: The experiment was conducted during 2006 and 2007 in the Demonstration Farm of the Faculty of Agriculture, University of Khartoum, Sudan to evaluate the effect of magnetizing technology on the hydraulic performance of drip irrigation system and emitters clogging under using four types of waters treated wastewater (WW), normal water (NW), magnetized wastewater (MWW) and magnetized normal water (MNW). The emitters average discharges during two years were 3.46, 2.65, 3.75 and 3.33 with NW, WW, MNW and MWW, respectively. The emission uniformity for two years 89% 71%, 96.5% and 87% with NW, WW, MNW and MWW respectively. The irrigation efficiencies were high with MNW, NW, MWW and WW respectively, in the first and second year.
Keywords: drip irrigation system, treated wastewater, magnetized wastewater, emission uniformity, irrigation efficiency.